I'll try to color idea, it's hard to make quest system understandable... but all quests should be doable. The desert doesn't have anything yet. Do you like the added battles?
The Help Water Lady quest doesn't work.
While it claims to need a cart like the First Stone quest, at the moment there is no means to obtain one for the former.
Due to the issues with water in the previous versions, I assumed that this meant that this quest is meant to activate water gathering, but that water gathering itself has not yet been implemented.
Like you said, the cart is needed to build the well. This time, there's a second village at around 7100m where you can get the cart. I updated the description of some two quests.
Your comment game me a good insight into how I can do quest description.
The problem is that said cart only activates the stone gathering, it does nothing for the Help Water Lady quest. (or was the intention to also obtain a cart in the first village?)